imx: mx6/7 enlarge CONFIG_SYS_BOOTM_LEN to 16M

Support uncompressing zImage which is larger than 8M.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Peter Robinson <pbrobinson@gmail.com>
Cc: Volodymyr Riazantsev <volodymyr.riazantsev@globallogic.com>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Adrian Alonso <aalonso@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/include/configs/mx6_common.h b/include/configs/mx6_common.h
index 174ea08..179b4f9 100644
--- a/include/configs/mx6_common.h
+++ b/include/configs/mx6_common.h
@@ -25,6 +25,8 @@
 
 #define CONFIG_SYS_NO_FLASH
 
+#define CONFIG_SYS_BOOTM_LEN	0x1000000
+
 #include <linux/sizes.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/imx-common/gpio.h>